High clarity low haze compositions

ABSTRACT

A first embodiment which is a bimodal polymer having a weight fraction of a lower molecular weight (LMW) component ranging from about 0.25 to about 0.45, a weight fraction of a higher molecular weight (HMW) component ranging from about 0.55 to about 0.75 and a density of from about 0.931 g/cc to about 0.955 g/cc which when tested in accordance with ASTM D1003 using a 1 mil test specimen displays a haze characterized by equation: % Haze=2145−2216*Fraction LMW −181*a molecular weight distribution of the LMW component (MWD LMW )−932*a molecular weight distribution of the HMW component(MWD HMW )+27*(Fraction LMW *MWD LMW )+1019*(Fraction LMW *MWD HMW )+73*(MWD LMW *MWD HMW ) wherein fraction refers to the weight fraction of the component in the polymer as a whole.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 14/284,704 filed on May 22, 2014, and entitled“Novel High Clarity Low Haze Compositions,” which is incorporated byreference herein in its entirety.

FIELD

The present disclosure relates to novel polymer compositions and filmmade from same, more specifically to polyethylene compositions for themanufacture of high clarity, low haze films.

BACKGROUND

Polyolefins are plastic materials useful for making a wide variety ofvalued products due to their combination of stiffness, ductility,barrier properties, temperature resistance, optical properties,availability, and low cost. In particular, polyethylene (PE) is one ofthe largest volume polymers consumed in the world. It is a versatilepolymer that offers high performance relative to other polymers andalternative materials such as glass, metal or paper. One of the mostvalued products is plastic films. Plastic films such as PE films aremostly used in packaging applications but they also find utility in theagricultural, medical and engineering fields.

PE films are manufactured in a variety of polymer grades that areusually differentiated by the polymer density such that PE films can bedesignated for example, low density polyethylene (LDPE), medium densitypolyethylene (MDPE) and, high density polyethylene (HDPE) wherein eachdensity range has a unique combination of properties making it suitablefor a particular application. Generally speaking, films prepared fromMDPE and HDPE display poor optical properties in terms of a high degreeof haze and low clarity. An ongoing need exists for MDPE and HDPEpolymer compositions having improved optical properties.

SUMMARY

Disclosed herein is a bimodal polymer having a weight fraction of alower molecular weight (LMW) component ranging from about 0.25 to about0.45, a weight fraction of a higher molecular weight (HMW) componentranging from about 0.55 to about 0.75 and a density of from about 0.931g/cc to about 0.955 g/cc which when tested in accordance with ASTM D1003using a 1 mil test specimen displays a haze characterized by equation: %Haze=2145-2216*Fraction_(LMW)−181*a molecular weight distribution of theLMW component (MWD_(LMW))−932*a molecular weight distribution of the HMWcomponent(MWD_(HMW))+27*(Fraction_(LMW)*MWD_(LMW))+1019*(Fraction_(LMW)*MWD_(HMW))+73*(MWD_(LMW)*MWD_(HMW))wherein fraction refers to the weight fraction of the component in thepolymer as a whole.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and theadvantages thereof, reference is now made to the following briefdescription, taken in connection with the accompanying drawings anddetailed description, wherein like reference numerals represent likeparts.

FIG. 1 is a size exclusion chromatograph overlay of samples from example1.

FIGS. 2 and 3 are deconvoluted size exclusion chromatographs of samplesfrom example 1.

FIG. 4 is a plot of the measured haze as a function of the lowermolecular weight fraction present for each sample from example 1.

FIG. 5 is a plot of the predicted haze as a function of the measuredhaze for the samples from example 1.

FIG. 6 is a plot of the measured clarity as a function of the lowermolecular weight fraction present for each sample from example 1.

FIG. 7 is a plot of the predicted clarity as a function of the measuredclarity for the samples from example 1.

DETAILED DESCRIPTION

Disclosed herein are polyethylene (PE) polymers, PE films, and methodsof making same. Such methods may comprise preparing a PE polymer andforming the PE polymer into a film. In an aspect, the PE polymercomprises a multimodal PE polymer and the film prepared therefrom maydisplay enhanced optical properties such as increased clarity andreduced haze.

The PE polymers of the present disclosure can be formed using anysuitable olefin polymerization method which may be carried out usingvarious types of polymerization reactors. As used herein,“polymerization reactor” includes any polymerization reactor capable ofpolymerizing olefin monomers to produce homopolymers or copolymers. Suchhomopolymers and copolymers are referred to as resins or polymers.

The various types of reactors include those that may be referred to asbatch, slurry, gas-phase, solution, high pressure, tubular, or autoclavereactors. Gas phase reactors may comprise fluidized bed reactors orstaged horizontal reactors. Slurry reactors can comprise vertical orhorizontal loops. High pressure reactors may comprise autoclave ortubular reactors. Reactor types can include batch or continuousprocesses. Continuous processes could use intermittent or continuousproduct discharge. Processes can also include partial or full directrecycle of un-reacted monomer, un-reacted co-monomer, and/or diluent.

Polymerization reactor systems of the present disclosure can compriseone type of reactor in a system or multiple reactors of the same ordifferent type. Production of polymers in multiple reactors can includeseveral stages in at least two separate polymerization reactorsinterconnected by a transfer device making it possible to transfer thepolymers resulting from the first polymerization reactor into the secondreactor. The desired polymerization conditions in one of the reactorscan be different from the operating conditions of the other reactors.Alternatively, polymerization in multiple reactors can include themanual transfer of polymer from one reactor to subsequent reactors forcontinued polymerization. Multiple reactor systems can include anycombination including, but not limited to, multiple loop reactors,multiple gas reactors, a combination of loop and gas reactors, multiplehigh pressure reactors, or a combination of high pressure with loopand/or gas reactors. The multiple reactors can be operated in series orin parallel.

According to one aspect of the disclosure, the polymerization reactorsystem can comprise at least one loop slurry reactor comprising verticaland/or horizontal loops. Monomer, diluent, catalyst and optionally anyco-monomer can be continuously fed to a loop reactor wherepolymerization occurs. Generally, continuous processes can comprise thecontinuous introduction of a monomer, a catalyst, and a diluent into apolymerization reactor and the continuous removal from this reactor of asuspension comprising polymer particles and the diluent. Reactoreffluent can be flashed to remove the solid polymer from the liquidsthat comprise the diluent, monomer and/or co-monomer. Varioustechnologies can be used for this separation step including but notlimited to, flashing that can include any combination of heat additionand pressure reduction; separation by cyclonic action in either acyclone or hydrocyclone; or separation by centrifugation.

A suitable slurry polymerization process (also known as the particleform process), is disclosed, for example, in U.S. Pat. Nos. 3,248,179,4,501,885, 5,565,175, 5,575,979, 6,239,235, 6,262,191, and 6,833,415,each of which is incorporated by reference herein in its entirety.

Suitable diluents used in slurry polymerization include, but are notlimited to, the monomer being polymerized and hydrocarbons that areliquids under reaction conditions. Examples of suitable diluentsinclude, but are not limited to, hydrocarbons such as propane,cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, andn-hexane. Some loop polymerization reactions can occur under bulkconditions where no diluent is used. An example is polymerization ofpropylene monomer as disclosed in U.S. Pat. No. 5,455,314, which isincorporated by reference herein in its entirety.

According to yet another aspect of this disclosure, the polymerizationreactor can comprise at least one gas phase reactor. Such systems canemploy a continuous recycle stream containing one or more monomerscontinuously cycled through a fluidized bed in the presence of thecatalyst under polymerization conditions. A recycle stream can bewithdrawn from the fluidized bed and recycled back into the reactor.Simultaneously, polymer product can be withdrawn from the reactor andnew or fresh monomer can be added to replace the polymerized monomer.Such gas phase reactors can comprise a process for multi-step gas-phasepolymerization of olefins, in which olefins are polymerized in thegaseous phase in at least two independent gas-phase polymerization zoneswhile feeding a catalyst-containing polymer formed in a firstpolymerization zone to a second polymerization zone. One type of gasphase reactor is disclosed in U.S. Pat. Nos. 5,352,749, 4,588,790, and5,436,304, each of which is incorporated by reference herein in itsentirety.

According to still another aspect of the disclosure, a high pressurepolymerization reactor can comprise a tubular reactor or an autoclavereactor. Tubular reactors can have several zones where fresh monomer,initiators, or catalysts are added. Monomer can be entrained in an inertgaseous stream and introduced at one zone of the reactor. Initiators,catalysts, and/or catalyst components can be entrained in a gaseousstream and introduced at another zone of the reactor. The gas streamscan be intermixed for polymerization. Heat and pressure can be employedappropriately to obtain optimal polymerization reaction conditions.

According to yet another aspect of the disclosure, the polymerizationreactor can comprise a solution polymerization reactor wherein themonomer is contacted with the catalyst composition by suitable stirringor other means. A carrier comprising an inert organic diluent or excessmonomer can be employed. If desired, the monomer can be brought in thevapor phase into contact with the catalytic reaction product, in thepresence or absence of liquid material. The polymerization zone ismaintained at temperatures and pressures that will result in theformation of a solution of the polymer in a reaction medium. Agitationcan be employed to obtain better temperature control and to maintainuniform polymerization mixtures throughout the polymerization zone.Adequate means are utilized for dissipating the exothermic heat ofpolymerization.

Polymerization reactors suitable for the present disclosure can furthercomprise any combination of at least one raw material feed system, atleast one feed system for catalyst or catalyst components, and/or atleast one polymer recovery system. Suitable reactor systems for thepresent disclosure can further comprise systems for feedstockpurification, catalyst storage and preparation, extrusion, reactorcooling, polymer recovery, fractionation, recycle, storage, loadout,laboratory analysis, and process control.

Conditions that are controlled for polymerization efficiency and toprovide resin properties include temperature, pressure, and theconcentrations of various reactants. Polymerization temperature canaffect catalyst productivity, polymer molecular weight and molecularweight distribution. Suitable polymerization temperature can be anytemperature below the de-polymerization temperature according to theGibbs free energy equation. Typically, this includes from about 60° C.to about 280° C., for example, and from about 70° C. to about 110° C.,depending upon the type of polymerization reactor.

Suitable pressures will also vary according to the reactor andpolymerization type. The pressure for liquid phase polymerizations in aloop reactor is typically less than 1000 psig. Pressure for gas phasepolymerization is usually at about 200 to about 500 psig. High pressurepolymerization in tubular or autoclave reactors is generally run atabout 20,000 to about 75,000 psig. Polymerization reactors can also beoperated in a supercritical region occurring at generally highertemperatures and pressures. Operation above the critical point of apressure/temperature diagram (supercritical phase) can offer advantages.

The concentration of various reactants can be controlled to produceresins with certain physical and mechanical properties. The proposedend-use product that will be formed by the resin and the method offorming that product determines the desired resin properties. Mechanicalproperties include tensile, flexural, impact, creep, stress relaxation,and hardness tests. Physical properties include density, molecularweight, molecular weight distribution, melting temperature, glasstransition temperature, temperature melt of crystallization, density,stereoregularity, crack growth, long chain branching and rheologicalmeasurements.

The concentrations of monomer, hydrogen, modifiers, and electron donorscan be utilized in producing these resin properties. Co-monomer is usedto control product density. Hydrogen can be used to control productmolecular weight. Modifiers can be used to control product propertiesand electron donors affect stereoregularity. In addition, theconcentration of poisons is minimized because poisons impact thereactions and product properties. In an embodiment, hydrogen is added tothe reactor during polymerization. Alternatively, hydrogen is not addedto the reactor during polymerization.

The polymer or resin can be formed into various articles, including, butnot limited to pipes, bottles, toys, containers, utensils, filmproducts, drums, tanks, membranes, and liners. Various processes can beused to form these articles, including, but not limited to, film blowingand cast film, blow molding, extrusion molding, rotational molding,injection molding, fiber spinning, thermoforming, cast molding, and thelike. After polymerization, additives and modifiers can be added to thepolymer to provide better processing during manufacturing and fordesired properties in the end product. Additives include surfacemodifiers such as slip agents, antiblocks, tackifiers; antioxidants suchas primary and secondary antioxidants; pigments; processing aids such aswaxes/oils and fluoroelastomers; and special additives such as fireretardants, antistats, scavengers, absorbers, odor enhancers, anddegradation agents.

The PE polymer can include other suitable additives. Such additives canbe used singularly or in combination and can be included in the polymercomposition before, during or after preparation of the PE polymer asdescribed herein. Such additives can be added via known techniques, forexample during an extrusion or compounding step such as duringpelletization or subsequent processing into an end use article. Hereinthe disclosure will refer to a PE polymer although a polymer compositioncomprising the PE polymer and one or more additives is alsocontemplated.

Any catalyst composition capable of producing a PE polymer of the typedisclosed herein can be employed in the production of the polymer. Forexample, a catalyst composition for the production of a PE polymer ofthe type disclosed herein can include at least two metallocenes that areselected such that the polymers produced therefrom have two distinctlydifferent molecular weights. The first metallocene can be atightly-bridged metallocene containing a substituent that includes aterminal olefin. The second metallocene is generally not bridged and ismore responsive to chain termination reagents, such as hydrogen, thanthe first metallocene. The metallocenes can be combined with anactivator, an aluminum alkyl compound, an olefin monomer, and an olefincomonomer to produce the desired polyolefin. The activity and theproductivity of the catalyst can be relatively high. As used herein, theactivity refers to the grams of polymer produced per gram of solidcatalyst charged per hour, and the productivity refers to the grams ofpolymer produced per gram of solid catalyst charged. Such catalysts aredisclosed for example in U.S. Pat. Nos. 7,312,283 and 7,226,886 each ofwhich is incorporated herein by reference in its entirety.

In an embodiment, a catalyst composition comprises a first metallocenecompound, a second metallocene compound, an activator and optionally anorganoaluminum compound. The first metallocene compound can becharacterized by the general formula:(X¹R¹)(X²R² ₂)(X³)(X⁴)M¹;wherein (X¹) is cyclopentadienyl, indenyl, or fluorenyl, (X²) isfluorenyl, and (X¹) and (X²) are connected by a disubstituted bridginggroup comprising one atom bonded to both (X¹) and (X²), wherein the atomis carbon or silicon. A first substituent of the disubstituted bridginggroup is an aromatic or aliphatic group having from 1 to about 20 carbonatoms. A second substituent of the disubstituted bridging group can bean aromatic or aliphatic group having from 1 to about 20 carbon atoms,or the second substituent of the disubstituted bridging group is anunsaturated aliphatic group having from 3 to about 10 carbon atoms. R¹is H, or an unsaturated aliphatic group having from 3 to about 10 carbonatoms. R² is H, an alkyl group having from 1 to about 12 carbon atoms,or an aryl group; (X³) and (X⁴) are independently an aliphatic group, anaromatic group, a cyclic group, a combination of aliphatic and cyclicgroups, or a substituted derivative thereof, having from 1 to about 20carbon atoms, or a halide; and M¹ is Zr or Hf. The first substituent ofthe disubstituted bridging group can be a phenyl group. The secondsubstituent of the disubstituted bridging group can be a phenyl group,an alkyl group, a butenyl group, a pentenyl group, or a hexenyl group.

The second metallocene compound can be characterized by the generalformula:(X⁵)(X⁶)(X⁷)(X⁸)M²;wherein (X⁵) and (X⁶) are independently a cyclopentadienyl, indenyl,substituted cyclopentadienyl or a substituted indenyl, each substituenton (X⁵) and (X⁶) is independently selected from a linear or branchedalkyl group, or a linear or branched alkenyl group, wherein the alkylgroup or alkenyl group is unsubstituted or substituted, any substituenton (X⁵) and (X⁶) having from 1 to about 20 carbon atoms; (X⁷) and (X⁸)are independently an aliphatic group, an aromatic group, a cyclic group,a combination of aliphatic and cyclic groups, or a substitutedderivative thereof, having from 1 to about 20 carbon atoms; or a halide,and M² is Zr or Hf.

In an embodiment of the present disclosure, the ratio of the firstmetallocene compound to the second metallocene compound can be fromabout 1:10 to about 10:1. According to other aspects of the presentdisclosure, the ratio of the first metallocene compound to the secondmetallocene compound can be from about 1:5 to about 5:1. According toyet other aspects of the present disclosure, the ratio of the firstmetallocene compound to the second metallocene compound can be fromabout 1:2 to about 2:1.

In an embodiment of the present disclosure, the activator can be a solidoxide activator-support, a chemically treated solid oxide, a claymineral, a pillared clay, an exfoliated clay, an exfoliated clay gelledinto another oxide matrix, a layered silicate mineral, a non-layeredsilicate mineral, a layered aluminosilicate mineral, a non-layeredaluminosilicate mineral, an aluminoxane, a supported aluminoxane, anionizing ionic compound, an organoboron compound, or any combinationthereof. The terms “chemically-treated solid oxide”, “solid oxideactivator-support”, “acidic activator-support”, “activator-support”,“treated solid oxide compound”, and the like are used herein to indicatea solid, inorganic oxide of relatively high porosity, which exhibitsLewis acidic or Brønsted acidic behavior, and which has been treatedwith an electron-withdrawing component, typically an anion, and which iscalcined. The electron-withdrawing component is typically anelectron-withdrawing anion source compound. Thus, the chemically-treatedsolid oxide compound comprises the calcined contact product of at leastone solid oxide compound with at least one electron-withdrawing anionsource compound. Typically, the chemically-treated solid oxide comprisesat least one ionizing, acidic solid oxide compound. The terms “support”and “activator-support” are not used to imply these components areinert, and such components should not be construed as an inert componentof the catalyst composition.

The organoaluminum compound used with the present disclosure can havethe formula:(R³)₃Al;in which (R³) is an aliphatic group having from 2 to about 6 carbonatoms. In some instances, (R³) is ethyl, propyl, butyl, hexyl, orisobutyl.

In an embodiment, the catalysts are chosen from compounds like thoserepresented by the chemical structures A and B with sulfated alumina asthe activator-support and with tri-isobutylaluminum (TIBA) as theco-catalyst.

The PE polymer and/or individual components of the PE polymer cancomprise a homopolymer, a copolymer, or blends thereof. In anembodiment, the PE polymer is a polymer of ethylene with one or morecomonomers such as alpha olefins. Examples of suitable comonomersinclude without limitation unsaturated hydrocarbons having from 3 to 20carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene,3-methyl-1-butene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene,1-decene, and mixtures thereof.

In an embodiment, the PE polymer is a multimodal resin. Herein, the“modality” of a polymer resin refers to the form of its molecular weightdistribution curve, i.e. the appearance of a graph of the polymer weightfraction, frequency, or number as a function of its molecular weight.The polymer weight fraction refers to the weight fraction of moleculesof a given size. A polymer resin can have two or more components thatmay be distinguishable from one another, for example based upon theirindividual composition and/or molecular weight distribution. A molecularweight distribution curve may be prepared for each individual componentof the polymer resin.

The molecular weight distribution curves for the individual componentsmay be superimposed onto a common chart to form the weight distributioncurve for the polymer resin as a whole. Upon such superimposition, theresultant curve for the polymer resin as a whole may be multimodal orshow n distinct peaks corresponding to n polymer components of differingmolecular weight distributions. For example, a polymer having amolecular weight distribution curve showing a single peak may bereferred to as a unimodal polymer, a polymer having a curve showing twodistinct peaks may be referred to as a bimodal polymer, a polymer havinga curve showing three distinct peaks may be referred to as a trimodalpolymer, etc. Polymers having molecular weight distribution curvesshowing more than one peak may be collectively referred to as multimodalpolymers or resins. Furthermore, the distinct peaks may correspond tocomponents exhibiting distinct characteristics. For example, a bimodalpolymer resin may show two distinct peaks corresponding to twoindividual components of differing molecular weights.

In an embodiment, the PE polymer is a bimodal PE resin. In suchembodiments, the PE polymer comprises a higher molecular weight (HMW)component and a lower molecular weight (LMW) component. In suchembodiments, the weight fraction of LMW component in the PE polymer mayrange from about 0.25 to about 0.45, alternatively from about 0.27 toabout 0.40, or alternatively from about 0.28 to about 0.39 while theweight fraction of the HMW component in the PE polymer may range fromabout 0.55 to about 0.75, alternatively from about 0.60 to about 0.73,or alternatively from about 0.61 to about 0.72.

The PE polymers disclosed herein may have a variety of properties andparameters described below either singularly or in combination. Anysuitable methodology may be employed for determination of theseproperties and parameters.

In an embodiment, the PE polymer as a whole may have a weight averagemolecular weight (M_(w)) ranging from about 125,000 g/mol to about225,000 g/mol, alternatively from about 130,000 g/mol to about 210,000g/mol, or alternatively from about 150,000 g/mol to about 200,000 g/mol.The M_(w) is defined by Equation 1:

$\begin{matrix}{{\overset{\_}{M}}_{w} = \frac{\Sigma_{i}N_{i}M_{i}^{2}}{\Sigma_{i}N_{i}M_{i}}} & (1)\end{matrix}$where N_(i) is the number of molecules of molecular weight M_(i). Allmolecular weight averages are expressed in gram per mole (g/mol).

The molecular weight distribution (MWD) of the PE polymer may becharacterized by determining the ratio of the M_(w) to the numberaverage molecular weight (M_(n)), which is also referred to as thepolydispersity index (PDI) or more simply as polydispersity. The PEpolymers of this disclosure as a whole may display a MWD of from about20 to about 40, alternatively from about 25 to about 37, oralternatively from about 30 to about 35. In an embodiment, the LMWcomponent of the PE polymer is characterized by a MWD of from about 4.5to about 10, alternatively from about 4.7 to about 9, or alternativelyfrom about 5 to about 8.5. In an embodiment, the HMW component of the PEpolymer is characterized by a MWD of from about 2 to about 4,alternatively from about 2.2 to about 3.2, or alternatively from about2.3 to about 3.

The PE polymers of this disclosure may have a melt index under a forceof 5 kg (I5) of from about 0.10 dg/min. to about 0.90 dg/min.,alternatively from about 0.5 dg/min. to about 0.85 dg/min., oralternatively from about 0.55 dg/min. to about 0.80 dg/min.

The PE polymers of this disclosure may have a melt index under a forceof 10 kg (110) of from about 0.5 dg/min. to about 4 dg/min.,alternatively from about 1 dg/min. to about 3 dg/min., or alternativelyfrom about 1.5 dg/min. to about 2.5 dg/min. The melt index (MI (I5, I10)represents the rate of flow of a molten resin through an orifice of0.0825 inch diameter when subjected to the indicated force at 190° C. asdetermined in accordance with ASTM D1238.

The PE polymers of this disclosure may have a high load melt index(HLMI) of from about 5 dg/min to about 15 dg/min, alternatively lessthan about 15 dg/min., alternatively less than about 12 dg/min., oralternatively less than about 10 dg/min. The HLMI represents the rate offlow of a molten resin through an orifice of 0.0825 inch diameter whensubjected to a force of 21.6 kg at 190° C. as determined in accordancewith ASTM D1238.

The PE polymers of this disclosure may be further characterized ashaving a density of from about 0.931 g/cc to about 0.955 g/cc,alternatively greater than about 0.930 g/cc, alternatively greater thanabout 0.935 g/cc, or alternatively greater than about 0.940 g/cc. Thedensity refers to the mass per unit volume of polymer and may bedetermined in accordance with ASTM D1505.

In an embodiment, a PE polymer of this disclosure is fabricated into afilm. The films of this disclosure may be produced using any suitablemethodology. In an embodiment, the polymeric compositions are formedinto films through a blown film process. In a blown film process,plastic melt is extruded through an annular slit die, usuallyvertically, to form a thin walled tube. Air is introduced via a hole inthe center of the die to blow up the tube like a balloon. Mounted on topof the die, a high-speed air ring blows onto the hot film to cool it.The tube of film then continues upwards, continually cooling, until itpasses through nip rolls where the tube is flattened to create what isknown as a lay-flat tube of film. This lay-flat or collapsed tube isthen taken back down the extrusion tower via more rollers. On higheroutput lines, the air inside the bubble is also exchanged. This is knownas Internal Bubble Cooling (IBC).

The lay-flat film is then either kept as such or the edges of thelay-flat are slit off to produce two flat film sheets and wound up ontoreels. Typically, the expansion ratio between die and blown tube of filmwould be 1.5 to 4 times the die diameter. The films are extruded using“HDPE film” or “high-stalk extrusion” conditions with a neck height(freeze line height) to die diameter ratio from about 6:1 to 10:1. Thedrawdown between the melt wall thickness and the cooled film thicknessoccurs in both radial and longitudinal directions and is easilycontrolled by changing the volume of air inside the bubble and byaltering the haul off speed. The films formed from PE polymers of thisdisclosure may be of any thickness desired by the user. Alternatively,the PE polymers of this disclosure may be formed into films having athickness of from about 0.1 mils (2.54 μm) to about 2 mils (50.8 μm),alternatively less than about 2 mils (50.8 μm), alternatively less thanabout 1.5 mils (38.1 μm), or alternatively less than about 1 mil (25.4μm).

Films formed from PE polymers of this disclosure may be characterized bya 1% secant modulus in the transverse direction (TD) of from about100,000 psi (690 MPa) to about 300,000 psi (2068 MPa), alternativelygreater than about 100,000 psi (690 MPa), alternatively greater thanabout 120,000 psi (825 MPa), or alternatively greater than about 150,000psi (1030 MPa) as determined in accordance with ASTM D882, using a testspecimen having a 1.0 mil thickness. In an embodiment, the films formedfrom PE polymers of this disclosure may be characterized by a 1% secantmodulus in the machine direction (MD) of from about 90,000 psi (620 MPa)to about 160,000 psi (1103 MPa), alternatively greater than about 95,000psi (655 MPa), alternatively greater than about 100,000 psi (690 MPa),or alternatively greater than about 120,000 psi (825 MPa) as determinedin accordance with ASTM D882, using a test specimen having a 1.0 milthickness.

Films formed from PE polymers of this disclosure may be characterized bya 2% secant modulus in the TD of from about 80,000 psi (551 MPa) toabout 200,000 psi (1379 MPa), alternatively greater than about 85,000psi (585 MPa), alternatively greater than about 100,000 psi (690 MPa),or alternatively greater than about 140,000 psi (965 MPa) as determinedin accordance with ASTM D882, using a test specimen having a 1.0 milthickness. In an embodiment, the films formed from PE polymers of thisdisclosure may be characterized by a 2% secant modulus in the MD of fromabout 75,000 psi (515 MPa) to about 125,000 psi (862 MPa), alternativelygreater than about 75,000 psi (515 MPa), alternatively greater thanabout 85,000 psi (585 MPa), or alternatively greater than about 100,000psi (690 MPa) as determined in accordance with ASTM D882, using a testspecimen having a 1.0 mil thickness.

The secant modulus is a measure of the rigidity or stiffness of amaterial. It is basically the applied tensile stress, based on the forceand cross-sectional area, divided by the observed strain at that stresslevel. It is generally constant before the material approaches the pointat which permanent deformation will begin to occur.

Films formed from PE polymers of this disclosure may be characterized bya Young's modulus in the TD of from about 110,000 psi (755 MPa) to about290,000 psi (1999 MPa), alternatively greater than about 110,000 psi(755 MPa), alternatively greater than about 135,000 psi (930 MPa), oralternatively greater than about 150,000 psi (1030 MPa) as determined inaccordance with ASTM D882, using a test specimen having a 1.0 milthickness. In an embodiment, the films formed from PE polymers of thisdisclosure may be characterized by a Young modulus in the MD of fromabout 100,000 psi (690 MPa) to about 180,000 psi (1241 MPa),alternatively greater than about 100,000 psi (690 MPa), alternativelygreater than about 125,000 psi (860 MPa) or alternatively greater thanabout 140,000 psi (965 MPa) as determined in accordance with ASTM D882,using a test specimen having a 1.0 mil thickness. Young's modulus, alsoreferred to as modulus of elasticity, is a measure of the stiffness of agiven material.

In an aspect, films formed from PE polymers of this disclosure have adart drop strength, also termed a dart impact strength, ranging fromabout 100 g to about 500 g, alternatively greater than about 100 g,alternatively greater than about 200 g, or alternatively greater thanabout 300 g as measured in accordance with ASTM D1709 Method A using atest specimen having a 1 mil thickness. The dart drop strength refers tothe weight required to cause 50% of tested films to fail by impact froma falling dart under specified test conditions. Specifically, one methodemploys the use of a dart having a 38 mm (1.5 in) head diameter droppedfrom a height of 0.66 m (26. in).

In an embodiment, films formed from PE polymers of this disclosure havean Elmendorf tear strength in the MD ranging from about 40 g to about150 g, alternatively greater than about 40 g, alternatively greater thanabout 50 g, or alternatively greater than about 75 g. In an embodiment,films formed from PE polymers of this disclosure have an Elmendorf tearstrength in the TD of from about 500 g to about 1200 g, alternativelygreater than about 500 g, alternatively greater than about 600 g, oralternatively greater than about 700 g. as measured in accordance withASTM D1922 using a test specimen having a 1.0 mil thickness. TheElmendorf tear strength refers to the average force required topropagate tearing through a specified length of plastic film or nonrigidsheeting on an Elmendorf-type tear tester. Specifically, test specimenshaving a pre-cut slit are contacted with a knife-tipped pendulum. Theaverage force required to propagate tearing is calculated from thependulum energy lost while tearing the test specimen. The tear may bepropagated either in the MD or TD.

In an embodiment, the films formed from the PE polymers of thisdisclosure have a Spencer impact of from about 0.5 J to about 1.8 J,alternatively greater than about 0.5 J, alternatively greater than about0.75 J, or alternatively greater than about 1.0 J as measured inaccordance with ASTM D3420 using a test specimen having a 1 milthickness. Spencer impact measures the energy necessary to burst andpenetrate the center of a specimen, mounted between two rings with a 3.5inch diameter. The following equation, Equation 2, may be used to obtainan impact value in joules:E=RC/100  (2)where E is the energy to rupture, Joules, C is the apparatus capacityand, R is the scale reading on a 0 to 100 scale.

In an embodiment, films formed from the PE polymers of this disclosureare characterized by a TD yield strength ranging from about 3500 psi (24MPa) to about 6500 psi (45 MPa), alternatively greater than about 3500psi (24 MPa), alternatively greater than about 4000 psi (27 MPa), oralternatively greater than about 4500 psi (30 MPa). In an embodiment,films formed from the PE polymers of this disclosure are characterizedby a MD yield strength ranging from about 2500 psi (17 MPa) to about4500 psi (31 MPa), alternatively greater than about 2500 psi (17 MPa),alternatively greater than about 3000 psi (20 MPa), or alternativelygreater than about 3100 psi (21 MPa).

In an embodiment, films formed from the PE polymers of this disclosureare characterized by a TD break strength ranging from about 8000 psi (57MPa) to about 10000 psi (69 MPa), alternatively greater than about 8300psi (57 MPa), alternatively greater than about 8500 psi (58 MPa), oralternatively greater than about 9000 psi (62 MPa). In an embodiment,films formed from the PE polymers of this disclosure are characterizedby a MD break strength ranging from about 9,000 psi (60 MPa) to about12,000 psi (83 MPa), alternatively greater than about 9000 psi (60 MPa),alternatively greater than about 10,000 psi (69 MPa), or alternativelygreater than about 11,000 psi (75 MPa). In an embodiment, films formedfrom the PE polymers of this disclosure are characterized by a TD breakstrain ranging from about 500% to about 700%, alternatively greater thanabout 500%, alternatively greater than about 525%, or alternativelygreater than about 550%. In an embodiment, films formed from the PEpolymers of this disclosure are characterized by a MD break strainranging from about 350% to about 450%, alternatively greater than 350%,alternatively greater than about 400%, or alternatively greater thanabout 440%.

The yield strength refers to the stress a material can withstand withoutpermanent deformation of the material while the yield strain refers toamount of deformation elongation that occurs without permanentdeformation of the material. The break strength refers to the tensilestress corresponding to the point of rupture while the break strainrefers to the tensile elongation in the indicated directioncorresponding to the point of rupture. The yield strength, yield strain,break strength, and break strain may be determined in accordance withASTM D882.

In an embodiment, films formed from the PE polymers of this disclosureare characterized by a haze of from about 5% to about 80%, alternativelyless than about 80%, alternatively less than about 40%, or less thanabout 20%. Haze is the cloudy appearance of a material caused by lightscattered from within the material or from its surface. The haze of amaterial can be determined in accordance with ASTM D1003. In anembodiment the haze of a film formed from the PE polymers of thisdisclosure are characterized by Equation (3):%Haze=2145−2216*Fraction_(LMW)−181*(MWD_(LMW))−932*(MWD_(HMW))+27*(Fraction_(LMW)*MWD_(LMW))+1019*(Fraction_(LMW)*MWD_(HMW))+73*(MWD_(LMW)*MWD_(HMW))  [Equation 3]

In an embodiment a film formed from a PE polymer of this disclosure maydisplay a haze of less than about 40%, alternatively less than about 20%and is further characterized by a weight fraction of the LMW componentranging from about 0.25 to about 0.45, a MWD of the LMW component offrom about 5.1 to about 8.3, a MWD of the HMW component ranging fromabout 2.3 to about 2.6. In an embodiment, films having a haze of greaterthan about 70% and further characterized by a weight fraction of the LMWcomponent ranging from about 0.50 to about 0.70, a MWD of the LMWcomponent ranging from about 4.4 to about 5.9, and a MWD of the HMWcomponent ranging from about 2 to about 2.3 are excluded from thisdisclosure.

In an embodiment, films formed from PE polymers of this disclosure arecharacterized by a clarity of from about 40% to about 90%, alternativelygreater than about 40%, alternatively greater than about 60%, oralternatively greater than about 80% as determined in accordance withASTM D1746. In an embodiment, the clarity of a film formed from the PEpolymers of this disclosure are characterized by Equation (4):%Clarity=1934*Fraction_(LMW)+139*(MWD_(LMW))+709*(MWD_(HMW))−60*(Fraction_(LMW)*MWD_(LMW))−819*(Fraction_(LMW)*MWD_(HMW))−47*(MWD_(LMW)*MWD_(HMW))−1632  [Equation 4]

Herein haze is defined as the percent of transmitted light that isscattered more than 2.5° from the direction of the incident beam whileclarity refers to the cloudiness of specimen prepared from the polymericcomposition.

In an embodiment, the films produced from PE polymers of the typedescribed herein have a gloss 60° of from about 20 to about 60, oralternatively greater than about 20, alternatively greater than about25, or alternatively greater than about 50 as determined in accordancewith ASTM D2457. The gloss of a material is based on the interaction oflight with the surface of a material, more specifically the ability ofthe surface to reflect light in a specular direction. Gloss is measuredby measuring the degree of gloss as a function of the angle of theincident light, for example at 60° incident angle (also known as “gloss60°”).

In an embodiment, films formed from the PE polymers of this disclosurehave an oxygen transmission rate (OTR) of from about 215 cc/100 in²/dayto about 140 cc/100 in²/day, alternatively less than about 215 cc/100in²/day, alternatively less than about 175 cc/100 in²/day, oralternatively less than about 150 cc/100 in² for a 1-mil film asmeasured in accordance with ASTM D3985. OTR is the measurement of theamount of oxygen gas that passes through a film over a given period.Testing may be conducted under a range of relative humidity conditionsat a range of temperatures. Typically, one side of the film is exposedto the oxygen permeant. As it solubilizes into the film and permeatesthrough the sample material, nitrogen sweeps the opposite side of thefilm and transports the transmitted oxygen molecules to a coulometricsensor. This value is reported as a transmission rate. When this rate ismultiplied by the average thickness of the material, the results areconsidered a permeability rate.

In an embodiment, the films formed from the PE polymers of thisdisclosure have an moisture vapor transmission rate (MVTR) of from about0.6 g-mil/100 in²/day to about 0.35 g-mil/100 in²/day, alternativelyless than about 0.60 g-mil/100 in²/day; alternatively less than about0.50 g-mil/100 in²/day, or alternatively less than about 0.45 g-mil/100in²/day for a 1-mil film as measured in accordance with ASTM F 1249 at100° F. and 90% relative humidity (RH). The MVTR measures passage ofgaseous H₂O through a barrier. The MVTR may also be referred to as thewater vapor transmission rate (WVTR). Typically, the MVTR is measured ina special chamber, divided vertically by the substrate/barrier material.A dry atmosphere is in one chamber, and a moist atmosphere is in theother. A 24-hour test is run to see how much moisture passes through thesubstrate/barrier from the “wet” chamber to the “dry” chamber underconditions which can specify any one of five combinations of temperatureand humidity in the “wet” chamber.

EXAMPLES

The invention having been generally described, the following examplesare given as particular embodiments of the invention and to demonstratethe practice and advantages thereof. It is understood that the examplesare given by way of illustration and are not intended to limit thespecification of the claims in any manner.

Example 1

Fifteen experimental resins of the type disclosed herein, designated1-15, were prepared. The polymerization conditions utilized to prepareeach resin sample are presented in Table 1.

TABLE 1 Sample# 1 2 3 4 5 6 7 8 Activator-Support Sulfated SulfatedSulfated Sulfated Sulfated Sulfated Sulfated Sulfated Alumina AluminaAlumina Alumina Alumina Alumina Alumina Alumina Feeder size (cc) 0.90.35 0.35 Activator-Support to 37 33 34 34 34 33 34 33 reactor(rounds/hr) Metallocene A to reactor 1.36 1.02 1.24 1.19 0.95 1.26 1.031.22 based on i-C4 (ppm) Metallocene B to reactor 1.44 1.28 1.31 1.260.86 1.33 1.29 1.11 based on i-C4 (ppm) Autoclave residence time 29 3130 31 31 30 30 30 (Min) Tiba to Reactor based on 83.7 75.8 72.2 73.768.8 77.9 76.8 72.5 i-C4 (ppm) Rx Temp (° F.) 201.0 201.1 192.1 196.7197.1 191.8 192.0 197.2 Ethylene (mol %) 16.3 13.4 13.4 16.1 12.6 15.814.0 14.0 1-hexene (mol %) 0.8 0.5 0.4 0.7 0.6 0.8 0.7 0.7 H₂ feedrate(lb/hr) 0.0254 0.0258 0.0261 0.0259 0.0155 0.0254 0.0259 0.0154Ethylene feed rate 50.4 51.4 50.7 51.1 51.3 51.4 50.9 51.3 (lb/hr)1-Hexene feed rate 1.7 1.7 0.3 1.7 1.6 1.6 1.8 1.7 (lb/hr) Total i-C4flow rate 52.4 52.3 52.8 52.1 52.3 52.0 52.3 52.3 (lb/hr) Solidsconcentration 43.1 44.3 44.1 43.7 45.5 44.0 44.0 44.7 (wt %) Polymerproduction 46.0 47.7 46.8 46.8 48.8 47.1 47.2 48.0 (lb/hr) Density(pellet) (g/cc) 0.9419 0.9409 0.9545 0.9464 0.9431 0.9495 0.9491 0.9448HLMI (pellet) 6.43 5.25 7.57 12.99 3.35 12.09 22.03 5.39 Sample# 9 10 1112 13 14 15 Activator-Support Sulfated Sulfated Sulfated SulfatedSulfated Sulfated Sulfated Alumina Alumina Alumina Alumina AluminaAlumina Alumina Feeder size (cc) 0.9 0.9 0.9 0.9 0.9 0.9Activator-Support to reactor 42 33 34 37 34 34 34 (rounds/hr)Metallocene A to reactor based 1.35 1.26 0.85 1.21 1.17 1.20 1.23 oni-C4 (ppm) Metallocene B to reactor based 1.42 1.32 1.07 1.27 1.23 1.261.29 on i-C4 (ppm) Autoclave residence time (Min) 30 30 32 31 30 30 31Tiba to Reactor based on i-C4 82.1 74.5 68.2 82.4 72.2 75.9 75.4 (ppm)Rx Temp (° F.) 200.8 196.5 197.2 196.8 197.1 197.1 191.8 Ethylene (mol%) 15.2 13.9 12.5 14.1 14.9 14.9 14.5 1-hexene (mol %) 0.7 0.7 0.7 0.70.3 0.3 0.8 H₂ feed rate(lb/hr) 0.0154 0.0155 0.0154 0.0155 0.01570.0157 0.0155 Ethylene feed rate (lb/hr) 51.0 51.4 52.3 51.1 43.4 51.151.1 1-Hexene feed rate (lb/hr) 1.7 1.6 1.6 1.7 0.3 0.4 1.6 Total i-C4flow rate (lb/hr) 52.3 52.0 52.2 52.3 53.2 53.1 52.0 Solidsconcentration (wt %) 43.8 44.3 45.3 44.3 39.6 43.8 44.3 Polymerproduction (lb/hr) 47.0 47.4 49.0 47.5 39.0 46.7 47.3 Density (pellet)(g/cc) 0.9453 0.9482 0.9479 0.9481 0.9493 0.9579 0.9513 HLMI (pellet)5.42 11.3 11.8 10.71 6.36 5.95 41.45

The resin M_(w), M_(w)/M_(n), Melt index (I5 and I10), HLMI, MFR anddensity of these resins are presented in Table 2.

TABLE 2 Mw I5 I10 HLMI MFR Density Sample ID (kg/mol) Mw/Mn (dg/min.)(dg/min.) (dg/min) (I21.6/I10) (g/cc) 1 178.9 30.8 0.64 1.63 6.4 3.90.9419 2 199.2 32.7 0.56 1.84 5.3 2.9 0.9409 3 190.7 34.4 0.79 1.86 7.64.1 0.9545 4 181.9 33.2 0.59 2.36 13.0 5.5 0.9464 5 284.4 28.8 0.14 0.773.4 4.4 0.9431 6 172.2 31.7 0.87 2.63 12.1 4.6 0.9495 7 185.5 34.7 0.703.78 22.0 5.8 0.9491 8 271.5 33.4 0.14 0.61 5.4 8.8 0.9448 9 263.3 26.10.18 0.97 5.4 5.6 0.9453 10 256.5 29.0 0.18 1.33 11.3 8.5 0.9482 11259.0 27.0 0.35 1.64 11.8 7.2 0.9479 12 242.1 29.8 0.27 1.20 10.7 8.90.9481 13 268.2 30.2 0.32 0.75 6.4 8.5 0.9493 14 270.1 31.1 0.25 0.926.0 6.5 0.9579 15 221.2 29.1 0.58 3.36 41.5 12.3 0.9513

The fifteen resins from Table 2 were formed into blown films using a1.5″ Davis-Standard blown film with a 2-inch die, 0.035 inch die gap, atan output rate of 29 lb/hr, a 4:1 blow up ratio (BUR), a 14 inch freezeline (neck) height an extrusion temperature profile of 205° C. to 210°C. across the extruder and die and 1.0 mil gauge. The thickness of thefilm may also be referred to as the film gauge. The properties of thefilm were evaluated and are presented in Table 3.

TABLE 3 Spencer Impact MD Tear TD Tear Clarity Sample ID Dart (g) (J)(g) (g) Haze % % 1 481 1.22 119  964 14.0 85.3 2 371 1.52 100  677 15.680.9 3 189 0.62 55 968 23.6 81.4 4 311 1.04 56 987 40.7 58.6 5 409 2.0432 448 71.8 13.9 6 NA NA NA NA 78.0 22.5 7 217 0.90 38 832 84.0 10.7 8590 2.08 34 606 85.5 8.5 9 592 2.07 31 585 88.6 7.5 10 499 2.04 36 61791.8 6.4 11 360 1.44 42 607 93.0 6.6 12 NA NA NA NA 93.2 6.4 13 399 1.2558 450 93.3 6.5 14 366 1.56 59 471 93.4 6.2 15 189 0.87 27 734 95.4 5.8

Comparison of size exclusion chromatography of a low haze example(sample 2) and a high haze example (sample 7) is shown in FIG. 1.Deconvolution of the SEC of samples 1-15 provided the fraction of LMWcomponent present in each sample in the addition to the MWD of both theLMW and HMW components. This data is presented in Table 4 and shown inFIGS. 2 and 3.

TABLE 4 ID Number LMW Fraction LMW MWD HMW MWD 1 0.34 5.20 2.35 2 0.398.25 2.09 3 0.39 6.42 2.55 4 0.45 5.13 2.40 5 0.50 4.59 2.00 6 0.56 5.892.35 7 0.56 5.89 2.33 8 0.51 5.18 2.01 9 0.52 4.67 2.03 10 0.61 4.382.00 11 0.65 5.28 2.00 12 0.60 4.24 2.07 13 0.55 4.76 2.26 14 0.56 4.642.11 15 0.70 4.42 2.00

The experimentally determined haze and clarity for samples 1-15 werecompared to the haze and clarity determined using Equations 3 and 4respectively. Table 5 presents the fraction of the LMW component, MWD ofthe LMW and HMW components and the measured and predicted haze. The dataare plotted in FIGS. 4 and 5. Table 6 presents the weight fraction ofthe LMW component, MWD of the LMW and HMW components and the measuredand predicted clarity. The data are plotted in FIGS. 6 and 7.

TABLE 5 Sample LMW LMW HMW Haze ID Fraction MWD MWD Measured (%)Predicted (%) 1 0.34 5.20 2.35 14.0 14.1 2 0.39 8.25 2.09 15.6 15.8 30.39 6.42 2.55 23.6 18.2 4 0.45 5.13 2.40 40.7 43.9 5 0.50 4.59 2.0093.0 93.3 6 0.56 5.89 2.35 85.5 88.2 7 0.56 5.89 2.33 88.6 86.9 8 0.515.18 2.01 93.3 79.9 9 0.52 4.67 2.03 93.4 88.8 10 0.61 4.38 2.00 78.091.3 11 0.65 5.28 2.00 71.8 73.2 12 0.60 4.24 2.07 91.8 93.7 13 0.554.76 2.26 93.2 80.9 14 0.56 4.64 2.11 84.0 86.6 15 0.70 4.42 2.00 95.485.2

TABLE 6 LMW LMW HMW Clarity (%) Sample fraction MWD MWD MeasuredPredicted 1 0.34 5.2 2.4 85 80 2 0.39 8.3 2.1 81 80 3 0.39 6.4 2.6 81 884 0.45 5.1 2.4 59 51 5 0.50 4.6 2.0 14 3 6 0.56 5.9 2.4 23 10 7 0.56 5.92.3 11 3 8 0.51 5.2 2.0 9 10 9 0.52 4.7 2.0 8 10 10 0.61 4.4 2.0 6 12 110.65 5.3 2.0 7 6 12 0.60 4.2 2.1 6 3 13 0.55 4.8 2.3 6 10 14 0.56 4.62.1 6 3 15 0.70 4.4 2.0 6 15

The data demonstrate the medium to high density PE polymers with acharacteristic bimodal architecture of this disclosure display thetypical film properties of medium to high density HMW PE resins (e.g.,dart and Elmendorf tear strength) but uncharacteristically display highclarity and low haze, generally associated with lower density materials.

ADDITIONAL DISCLOSURE

The following enumerated embodiments are provided as non-limitingexamples.

A first embodiment which is a bimodal polymer having a weight fractionof a lower molecular weight (LMW) component ranging from about 0.25 toabout 0.45, a weight fraction of a higher molecular weight (HMW)component ranging from about 0.55 to about 0.75 and a density of fromabout 0.931 g/cc to about 0.955 g/cc which when tested in accordancewith ASTM D1003 using a 1 mil test specimen displays a hazecharacterized by equation: % Haze=2145−2216*Fraction_(LMW)−181*amolecular weight distribution of the LMW component (MWD_(LMW))−932*amolecular weight distribution of the HMWcomponent(MWD_(HMW))+27*(Fraction_(LMW)*MWD_(LMW))+1019*(Fraction_(LMW)*MWD_(HMW))+73*(MWD_(LMW)*MWD_(HMW))wherein fraction refers to the weight fraction of the component in thepolymer as a whole.

A second embodiment which is the polymer of the first embodiment whichwhen tested in accordance with ASTM D1746 displays a claritycharacterized by equation: %Clarity=1934*Fraction_(LMW)+139*(MWD_(LMW))+709*(MWD_(HMW))−60*(Fraction_(LMW)*MWD_(LMW))−819*(Fraction_(LMW)*MWD_(HMW))−47*(MWD_(LMW)*MWD_(HMW))−1632.

A third embodiment which is the polymer of any of the first throughsecond embodiments having a molecular weight distribution of from about20 to about 40.

A fourth embodiment which is the polymer of any of the first throughthird embodiments wherein the LMW component has a molecular weightdistribution of from about 4.5 to about 10.

A fifth embodiment which is the polymer of any of the first throughfourth embodiments wherein the HMW component has a molecular weightdistribution of from about 2 to about 4.

A sixth embodiment which is the polymer of any of the first throughfifth embodiments having a high load melt index of from about 5 dg/min.to about 15 dg/min.

A seventh embodiment which is the polymer of any of the first throughsixth embodiments which when tested in accordance with ASTM D882 has a1% secant modulus in the transverse direction of from about 100,000 psito about 300,000 psi.

An eighth embodiment which is the polymer of any of the first throughseventh embodiments which when tested in accordance with ASTM D882 has a1% secant modulus in the machine direction of from about 90,000 psi toabout 160,000 psi.

A ninth embodiment which is the polymer of any of the first througheighth embodiment which when tested in accordance with ASTM D1709 has adart drop strength ranging from about 100 g to about 500 g.

A tenth embodiment which is the polymer of any of the first throughninth embodiments which when tested in accordance with ASTM D1922 has anElmendorf tear strength in the machine direction ranging from about 40 gto about 150 g.

An eleventh embodiment which is the polymer of any of the first throughtenth embodiments which when tested in accordance with ASTM D1922 has anElmendorf tear strength in the transverse direction ranging from about500 g to about 1200 g.

A twelfth embodiment which is the polymer of any of the first througheleventh embodiments which when tested in accordance with ASTM D3420 hasSpencer impact of from about 0.5 J to about 1.8 J.

A thirteenth embodiment which is the polymer of any of the first throughtwelfth embodiments which when tested in accordance with ASTM D882 has ayield strength in the transverse direction ranging from about 3500 psito 6500 psi.

A fourteenth embodiment which is the polymer of any of the first throughthirteenth embodiments which when tested in accordance with ASTM D882has a yield strength in the machine direction ranging from about 2500psi to about 4500 psi.

A fifteenth embodiment which is the polymer of any of the first throughfourteenth embodiments which when tested in accordance with ASTM D882has a break strength in the transverse direction ranging from about 8000psi to about 10000 psi.

A sixteenth embodiment which is the polymer of any of the first throughfifteenth embodiments which when tested in accordance with ASTM D882 hasa break strength in the machine direction ranging from about 9000 psi toabout 12000 psi.

A seventeenth embodiment which is the polymer of any of the firstthrough sixteenth embodiments which when tested in accordance with ASTMD882 has a break strain in the transverse direction ranging from about500% to about 700%.

An eighteenth embodiment which is the polymer of any of the firstthrough seventeenth embodiments which when tested in accordance withASTM D882 has a break strain in the machine direction ranging from about350% to about 450%.

A nineteenth embodiment which is the polymer of any of the first througheighteenth embodiments which when tested in accordance with ASTM D3985has an oxygen transmission rate of from about 215 cc/100 in²/day toabout 140 cc/100 in²/day.

A twentieth embodiments which is the polymer of any of the first throughnineteenth embodiments which when tested in accordance with ASTM F1249has a moisture vapor transmission rate of from about 0.6 g-mil/100in²/day to about 0.35 g-mil/100 in²/day.

A twenty-first embodiment which is the polymer of any of the firstthrough twentieth embodiments which when tested in accordance with ASTMD2457 has a gloss 60° of from about 20 to about 60.

A twenty-second embodiment which is the polymer of any of the firstthrough twenty-first embodiments which when tested in accordance withASTM D1003 has a percentage haze less than about 40%.

Without further elaboration, it is believed that one skilled in the artcan, using the description herein, utilize the present invention to itsfullest extent. While inventive aspects have been shown and described,modifications thereof can be made by one skilled in the art withoutdeparting from the spirit and teachings of the invention. Theembodiments and examples described herein are exemplary only, and arenot intended to be limiting. Many variations and modifications of theinvention disclosed herein are possible and are within the scope of theinvention. Where numerical ranges or limitations are expressly stated,such express ranges or limitations should be understood to includeiterative ranges or limitations of like magnitude falling within theexpressly stated ranges or limitations (e.g., from about 1 to about 10includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13,etc.). Use of the term “optionally” with respect to any element of aclaim is intended to mean that the subject element is required, oralternatively, is not required. Both alternatives are intended to bewithin the scope of the claim. Use of broader terms such as comprises,includes, having, etc. should be understood to provide support fornarrower terms such as consisting of, consisting essentially of,comprised substantially of, etc.

Accordingly, the scope of protection is not limited by the descriptionset out above but is only limited by the claims which follow, that scopeincluding all equivalents of the subject matter of the claims. Each andevery claim is incorporated into the specification as an embodiment ofthe present invention. Thus, the claims are a further description andare an addition to the embodiments of the present invention. Thedisclosures of all patents, patent applications, and publications citedherein are hereby incorporated by reference, to the extent that theyprovide exemplary, procedural or other details supplementary to thoseset forth herein.

What is claimed is:
 1. A bimodal polymer having a weight fraction of alower molecular weight (LMW) component ranging from about 0.25 to about0.45, a weight fraction of a higher molecular weight (HMW) componentranging from about 0.55 to about 0.75 and a density of from about 0.931g/cc to about 0.955 g/cc which when tested in accordance with ASTM D1003using a 1 mil test specimen displays a haze characterized by equation: %Haze=2145−2216*Fraction_(LMW)−181* a molecular weight distribution ofthe LMW component (MWD_(LMW))−932* a molecular weight distribution ofthe HMW component(MWD_(HMW))+27*(Fraction_(LMW)*MWD_(LMW))+1019*(Fraction_(LMW)*MWD_(HMW))+73*(MWD_(LMW)*MWD_(HMW))wherein fraction refers to the weight fraction of the component in thepolymer as a whole, wherein the bimodal polymer is produced by:contacting a polymerization catalyst and monomer in the presence ofhydrogen in one or more polymerization reactors to yield the bimodalpolymer.
 2. The bimodal polymer of claim 1, wherein the one or morepolymerization reactors is selected from batch, slurry, gas-phase,solution, high pressure, tubular, autoclave, or combinations thereof. 3.The bimodal polymer of claim 1, wherein the one or more polymerizationreactors comprises multiple loop reactors, multiple gas phase reactors,a combination of one or more loop reactors and one or more gas phasereactors, multiple high pressure reactors, or a high pressure reactor incombination with a loop reactor and/or a gas phase reactor.
 4. Thebimodal polymer of claim 1, wherein the polymerization catalystcomprises a dual metallocene catalyst system.
 5. The bimodal polymer ofclaim 4, wherein the dual metallocene catalyst system comprises atightly bridged metallocene compound having a substituent that includesa terminal olefin and an unbridged metallocene compound.
 6. The bimodalpolymer of claim 4, wherein the polymerization catalyst furthercomprises an activator.
 7. The bimodal polymer of claim 6, wherein theactivator comprises an organoaluminum compound.
 8. The bimodal polymerof claim 4, wherein the one or more polymerization reactors comprisesmultiple loop reactors, multiple gas phase reactors, a combination ofone or more loop reactors and one or more gas phase reactors, multiplehigh pressure reactors, or a high pressure reactor in combination with aloop reactor and/or a gas phase reactor.
 9. The bimodal polymer of claim1, wherein the polymerization catalyst is a polymerization catalystsystem comprising: a first catalyst composition which contacts themonomer in the presence of hydrogen in a first polymerization reactor ofthe one or more polymerization reactors under conditions sufficient toyield a first polymer product; and a second catalyst composition whichcontacts the monomer in the presence of hydrogen in a secondpolymerization reactor of the one or more polymerization reactors underconditions sufficient to yield a second polymer product; wherein thefirst polymer product, the second polymer product, or both the firstpolymer product and the second polymer product is the bimodal polymer.10. The bimodal polymer of claim 9, wherein the first catalystcomposition comprises a tightly bridged metallocene compound having asubstituent that includes a terminal olefin, wherein the second catalystcomposition comprises an unbridged metallocene compound.
 11. The bimodalpolymer of claim 1, wherein the monomer is ethylene, and wherein thebimodal polymer is a polyethylene polymer.
 12. A film formed from abimodal polymer having a weight fraction of a lower molecular weight(LMW component ranging from about 0.25 to about 0.45, a weight fractionof a higher molecular weight (HMW) component ranging from about 0.55 toabout 0.75 and a density of from about 0.931 g/cc to about 0.955 g/ccwhich when tested in accordance with ASTM D1003 using a 1 mil testspecimen displays a haze characterized by equation:%Haze=2145−2216*Fraction_(LMW)−181* a molecular weight distribution ofthe LMW component (MWD_(LMW))−932*a molecular weight distribution of theHMWcomponent(MWD_(HMW))+27*(Fraction_(LMW)*MWD_(LMW))+1019*(Fraction_(LMW)*MWD_(HMW))+73*(MWD_(LMW)*MWD_(HMW))wherein fraction refers to the weight fraction of the component in thepolymer as a whole.
 13. The film of claim 12, comprising a polyethylenebimodal polymer.
 14. An article formed from a bimodal polymer having aweight fraction of a lower molecular weight (I,MW) component rangingfrom about 0.25 to about 0.45, a weight fraction of a higher molecularweight (HMW) component ranging from about 0.55 to about 0.75 and adensity of from about 0.931 g/cc to about 0.955 g/cc which when testedin accordance with ASTM D1003 using a 1 mil test specimen displays ahaze characterized by equation: %Haze=2145−2216*Fraction_(LMW)−181*amolecular weight distribution of the LMW component (MWD_(LMW))−932*amolecular weight distribution of the HMWcomponent(MWD_(HMW))+27*(Fraction_(LMW)*MWD_(LMW))+1019*(Fraction_(LMW)*MWD_(HMW))+73*(MWD_(LMW)*MWD_(HMW)) wherein fraction refers to theweight fraction of the component in the polymer as a whole.
 15. Thearticle of claim 14, selected from a pipe, a bottle, a toy, a container,a utensil, a film product, a drum, a tank, a membrane, and a liner. 16.The article of claim 14, wherein the bimodal polymer is a polyethylenepolymer.
 17. A process for producing a bimodal polymer comprising:contacting a polymerization catalyst and monomer in the presence ofhydrogen in one or more polymerization reactors to yield the bimodalpolymer, wherein the bimodal polymer has a weight fraction of a lowermolecular weight (LMW) component ranging from about 0.25 to about 0.45 aweight fraction of a higher molecular weight (HMW) component rangingfrom about 0.55 to about 0.75 and a density of from about 0.931 g/cc toabout 0.955 g/cc which when tested in accordance with ASTM D1003 using a1 mil test specimen displays a haze characterized by equation: % Haze=2145−2216*Fraction_(LMW)−181*a molecular weight distribution of the LMWcomponent (MWD_(LMW))−932*a molecular weight distribution of the HMWcomponent(MWD_(HMW))+27*(Fraction_(LMW)*MWD_(LMW))+1019*(Fraction_(LMW)*MWD_(HMW))+73*(MWD_(LMW)*MWD_(HMW))wherein fraction refers to the weight fraction of the component in thepolymer as a whole.